I ran across a problem I cannot figure out how to solve. I have to consolidate data from 4 temporary tables to one permanent. I am using INNER JOIN for three temp tables and LEFT OUTER JOIN for fourth one. The problem is in data. Some records have duplicate IDs. So when I perform INSERT INTO instead of two records in perm table I got four. This happened so far twice but there is no guarantee that it would not happen again. Any suggestions how to solve it?